There is a method for performing, upon detection of deterioration in a communication status, communication by carrying out channel switching and using a different frequency. In this method, a transmitter transmits, to a receiver, a frame for providing a channel switching instruction, thereby realizing channel switching.
In the foregoing method, exchange of an instruction frame for providing a channel switching instruction is performed after detection of deterioration in a communication environment; therefore, when the environment is abruptly deteriorated, the exchange of the instruction frame might end in failure. When the exchange has ended in failure, channel switching cannot be carried out, and communication cannot be continued.